The installation of a massive railway bridge in extremely constricted conditions on a precipitous site presents a whole series of challenges. A difficult crane job, fiddly and complex – just the job for Uwe Langer. The boss of Riga-Mainz completed precisely this job in Bad Wimpfen, Baden-Württemberg with his team and a Liebherr LR 1600/2 crawler crane on behalf of Deutsche Bahn.
The expansion of the municipal railway around Heilbronn was what made the construction of a new railway bridge in Bad Wimpfen necessary. However, there was very little space on the precipitous site for the crawler crane to hoist the 355-ton steel bridge and to deliver the component. Proposals for using two cranes to position the bridge were rejected. For this solution the enormous truss construction would have had to be stored between the cranes for the duration of the set-up work. However, as the Deutsche Bahn project was already running behind, the whole thing had to be handled very quickly.
The Riga-Mainz team set up the Liebherr crawler crane on two massive reinforced concrete ramps. Company boss Uwe Langer, who was also responsible for planning the foundation, had a dozen piles driven into the site for this purpose down to a depth of up to 13 meters. After all, the ramp had to withstand a calculated crawler pressure of 507 kilo-newton per square meter.
During the night before the bridge was actually hoisted the 40 meter truss construction was transported from the assembly site to the construction site on two parallel self-propelled modular transporters (SPMTs) with ten axles each. To thread the two supports for securing the handling equipment through the trusses, the experts from Mainz fitted an extension on one side of each of them. This enabled a support crane on the other side of the bridge to handle them and draw the main support into the structure.
Only one crane
This was one of the smart ideas that led to Riga-Mainz being awarded the order for the work. “Riga was the only supplier to offer a solution using just one crane”, explained Kathrin Gottschang from the project management team at DB Projektbau GmbH, “the concept suggested by Uwe Langer was also the only one that included threaded the cross beam through the bridge trusses.” All the other suppliers would have fastened the crane at the top of the structure. That would have meant, however, that much of the work on the bridge could not have been carried out in advance of the hoisting work. “If we had had a bad winter, we would have fallen even further behind”, says Gottschang. “But this meant that we reduced the winter risk to almost zero.”
402 tons hoist
With the cross beam and attachment equipment the LR 1600/2 hoisted a total of 402 tons. The crawler crane was fitted with a total of 565 tons of ballast for the hoist. Slowly the crawlers reversed around ten meters until finally the bridge was positioned with pinpoint accuracy on the new abutments. Two other Liebherr cranes, an LTM 1200-5.1 and an LTF 1045-4.1, were used for set-up and support work.